Polling has consistently shown President Obama with a lead in Pennsylvania, but in recent weeks the size of that lead has narrowed, suggesting that Pennsylvania may be more of a question mark than had previously been thought.

Vice President Joe Biden, who was born in Scranton, will hold a campaign event in Pennsylvania Nov. 1.

ABC News currently rates the state as leaning Democrat. If it were to turn toward Romney in the last week of the election, that would suggest major cracks in the president's electoral firewall. The state has voted Democratic in the past five presidential elections. It hasn't gone Republican since 1988, and Democrats boast a huge advantage in terms of party registration. A little more than 4.2 million Democrats are registered in the state as compared to a little more than 3.1 million Republicans.

However, Pennsylvania's unemployment rate is slightly above the national average ? 8.2 percent as of September 2012 -- and Republicans have had success there in recent years. In the 2010 midterm elections Republican Tom Corbett picked up the governor's mansion and Pat Toomey, als a Republican, won a Senate seat.

Democratic Sen. Bob Casey is also running for reelection in 2012 and had thought to be in a strong position, but Republican Tom Casey, a former coal plant owner, has poured nearly $17 million of his own money into the Senate race. A tight Senate contest could energize conservatives to the polls.

Bob Casey was first elected to the Senate in 2006 when he unseated Republican Rick Santorum. Santorum was Romney's stiffest competition in the Republican primary earlier this year.

Check out the 'Electoral States of America' Battleground states map with latest polls and information HERE.

The Romney campaign still has not spent any money advertising in Pennsylvania, while the Obama campaign has spent a relatively low $5 million, according to tracking figures from the National Journal. As Election Day looms, those spending numbers go up if polling continues to indicate that the race is tight. The state's 20 electoral college votes are a big prize, and if Romney can pull off a last minute upset in the Keystone state, it will change the electoral map entirely.

Some key statistics about Pennsylvania:
CURRENT UNEMPLOYMENT RATE (source: BLS)
8.2 percent as of September 2012.

TREND SINCE OBAMA TOOK OFFICE.
When Obama took office in January 2009 the unemployment rate in Pennsylvania was 6.8 percent. The rate peaked at 8.7 percent in February and March 2010, and it has slowly dropped down over the course of the past two years, hovering between 7 and 8 percent.

MEDIAN HOUSEHOLD INCOME:
2011: $50,228
2008: $52,617

FORECLOSURES:
One in every 1,513 housing units as of September 2012.
29th in the U.S., where the average foreclosure rate is 1 in 730 housing units.